Fuel supplying means for jet engines



March 24, J. J W

FUEL SUPPLYING MEANS FOR JET ENGINES 2 SHEETS-SHEET 1 Filed April 19,1948 INVENTOR:

I John J. Wall, BY I yYZ/m W ATTORNEY- March 24, 1953 J. J. WALL FUELSUPPLYING MEANS FOR JET ENGINES "2 SHEETSSHEET 2 Filed April 19, 1948INVEN J OR: John J. Wall,

ATTORNEY.

My 88 2 x i 3 TE A UQ Patented Mar. 24, 1953 UNITED STATES n'rsu'rOFFICE 4 Claims.

My improvement pertains, generally, to jet engines in which theexplosive force of fuel, burned therein in a combustion chamber andleaving the engine in a jet, provides a driving thrust to propel thebody of an airplane, boat, or other vehicle. More specifically, myimprovement pertains to engines capable of producin jets of theintermittent type; that is, short blasts rapidly succeeding each other,the series of explosions necessary for that purpose being effected byadmission of a fuel-andair mixture into a combustion chamber and bybeing ignited therein.

While this type of engine is already well known, the specific object ofmy improvement is to provide an engine of higher efficiency, this by theimproved manner of supplying fuel to the combustion chamber by effectinga better commingling of air and fuel before the mixture reached thecombustion chamber and by improved means of controlling the rapidity ofthe sequence of explosions within said combustion chamber. Anotherobject of my improvement is to provide means whereby the fuel to be usedin producing gases by means of combustion is delivered in most dispersedcondition and already heated to a relatively high temperature in orderto aid in the expansion and dispersion of the fuel when deliveredtowards the combustion chamber by means of special nozzles used for thatpurpose.

Another object of my improvement is to provide automatic means to keepthe fuel at a desired temperature before it is released by said nozzles.A further object is to provide a jet engine which utilizes a highlyvolatile fuel, such as propane, for starting and, after warming up tothe proper operating temperature, automatically switches over to the useof a less volatile and more economical fuel such as kerosene or fueloil.

I shall now describe my improvement with eference to the accompanyingdrawings in which:

Figure 1 is a side elevation of my engine with auxiliary elements shownin a diagrammatic presentation; I a

Figure 2 is a longitudinal, sectional view of a front part of the engineincluding the intake for air and fuel, the combustion chamber, andcontrol elements interposed therebetween;

Figure 3 is an enlarged, sectional view of the elements interposedbetween the intake and the combustion chambers of the engine, the viewpresenting certain elements in different operative positions than shownin Figure 2;

Figure 4 is an exploded, perspective view of the v principal elementsdisposed between the intake end and the combustion chamber of theengine; Figure 5 is an enlarged, perspective view of the flame-arrestingmeans being a part of my engine assembly;

Figure 6 is a sectional view taken on line 6-6 of Figure 1;

Figure 7 is a sectional view taken on line 1-1 of Figure 1;

Figure 8 is a side elevation of a modified species oftemperature-control means for fuel conducting pipe in my engineassembly;

Figure 9 is a sectional View taken on line 9-9 of Figure 8.

Similar numerals refer to similar parts throughout the several views.

Basically, the engine includes three primary parts: The charging tube atthe .front, the combustion chamber in the middle and the discharge tubeat the end. All these parts are made of sheet metal, being connected,end to end, in an axial relation to each other as best shown in Figures1 and 2. The charging tube, generally indicated by numeral Iil, consistsof a cylinder 3 fully open at the front and opening, at its inner end,into a member I4 made in the form of a frustum Of a cone which expandsin the direction away from the cylinder I3.

Provided with a threaded rim I5, said member i l is threaded into anannular clamp I6 provided with an annular flange ll. Joined to saidclamp i6 in an axial relation thereto, by means of a flange I8, is aclamp l9, threaded on its inner side at 2%, said threaded portionserving as a means of connecting the above-said combustion chamber l ito the front end of the engine.

interposed between the charging tube [0 and the combustion chamber I iis what may be called an air diffuser, generally indicated by numeral 2!This is a circular structure including an annular frame 22 having itsinterior space divided by a diametrical partition 23. A plurality offins Ed, disposed parallel in a spaced relation to each other, extend ineach one-half of the interior space of the frame from said partition 23to the circular wall frame 22, the spaces 25 between the fins being opento provide passageways for entry of combustible mixture from a shutter26 made in the form ofa circular disc provided with a plurality of slots21, the slots being disposed parallel to and in a spaced relation toeach other, to correspond to the spacing of openings 25 in the diffuserwhich was described above. The slots are arranged in two rows on eachside of the central web 28 which, when the shutter is in position, isaligned with partition 23 in said diffuser.

Disposed directly behind the shutter so as to face it, is aflame-arrester. This includes a drum-like casing 29 of a diameter equalto that of the diffuser, the inner space of the casing being divided byparallel partitions 29a into a plurality of chambers 39, each chamberbeing open toward the front and towards the rear, as shown by numeral35, and each containing a core 3!. The core is made up Of a number ofcore rugated, thin metal plates 32 arranged in layers, one upon theother, but separated from each other by flat sheet-metal plates 33. Thisresults in the formation of a plurality of small channels 3% disposedparallel to the axis of the engine and open towards the front andtowards the rear. The above-said open ends of chamber 30 are arranged ina manner to correspond to the openingsZ'i in shutter 26. Thecore-forming members are retained in place within the drum 29 by meansof a circular plate 29b having therein apertures 29c opening into therespective chamhers 39.

The above-said members, that is, the diffuser, the shutter and the flamearrester are held in alignment in their relative positions with respectto the charging tube of the engine and the co 1.- bustion chamber bymeans of said connecting clamps, l5 and 19, the latter having a shoulder35, on its inner side, to act as a means of keeping the flame-arresterin place, in abutment with the shutter 25, the latter again being heldin 3=for pivotal connection, by means of bolt 56,

to arm il of a two-arm lever indicated generally by numeral 32 andfulcrumed at M. An

extension lla on arm l! fits into a yoke 86 cushioned at top and bottomby alayer of rubber 8?. The opposite arm of lever 52 is connected bymeans of a short rod- 45 to a piston :38 in a short cylinder ll disposedradially with respect to, and opening into, the combustion chamber H asbestshown in Figure2. 7 As will be described hereinbelow, the shutter isadapted to be moved, reciprocably, up and down; first to admit a chargeof fuel and air into the combustion chamber, and then to close thecombustion chamber preliminary to the explosion of the charge withinsaid chamber.

In order to time the operation of the shutter for the best'efiicie'ncyof the engine, I have devised means whereby said operation of theshutter may be accelerated or delayed with respect to the time. of theexplosion of a charge within the combustion chamber. The means include avshort, leaf spring :38, one end of which fits loosely. into a slot asin the end of extension ila ofarm ii: of lever 42. The ,opposite'end ofthe spring isafflxed to'an arm Eli-f a lever the lever being fulcrumedat 52 and having an arm 53 for selective connection, along anarcuatemember ddj'mounted on a bracket 55, Which'is afiixed to member. M or thebody of theeng-ine. The pur-v an electric motor pipe closed in tank lit.fuels creates some pressure within the tank.

'15, each arm being discharge nozzle 75a.

pose of the mechanism just described is to cause the free end of thespring to exert pressure against the body of the shutter upwardly ordownwardly as the case may be. The operation of the mechanism will bedescribed below.

I shall now describe means designed by me to supply the engine with thenecessary fuel for combustion therein. Some of the elements provided byme for that purpose-such as heating pipes and switchesare located on thebody of the engine as already described; other elements such as tanks,motors, etc.are located in the body of the vehicle which is to bepropelled by my engine, such a body being, for instance, the fuselage ofa plane.

I have found it desirable to use in my engine,

in the initial stages of its operation, when the parts, of the body ofthe engine are relatively cold, a fuel of high volatility such aspropane, methane or naphtha, a quantity of which is en- Naturalevaporation'of such However, to insure a sufficient degree of pressurefor starting and Warming up the engine, I have provided a small aircompressor operated by The operation of the motor would force into tank55 a quantity of air through Forced out under the pressure of gas or airwithin tank 58, fuel for the operation of the engine is conveyed theretoby means of a tube a number of switches and thermostatic controls whichare all connected to an electric battery indicated here, generally, bynumeral 655. These controls will be mentioned, one by one, in the courseof the details of the description of the elements of my engine.

Resuming the description of the means to convey fuel towards the body ofthe engine, I wish to point out that tube 62 for conveyance of fuel fromtank 56 is also provided with a check valve 65 which permits passage offluid in only one direction namely, out of the tank. A T 67! joins Ltube52 leading to a fuel-heating unit mounted upon the outer surface ofdischarge tube ii, in-

dicated generally by numeral to.

For the purpose of description,'the unit may consist of a single pipereversely bent upon itself inhair-Din loops to form several parallellengths of said pipe, one length of the pipe forming the bottom memberand the other members being disposed one above the other as shown inFigure 1. Individual lengths of pipe, "as best shown therein, arindicated by numeral it, the loops at the end being indicated by numeralH. The outer end of the pipe, marked leads into fuel line i3 which iscovered by an insulating coat "it and is mounted on the outside of thecombustion chamber andthe outside of the intake end of said engine. Asbest shown in Figure 1, said fuel line lSleads to the front end ofcharging tube is andterminates in a two-arm, hollow bracket 7 equippedwith a fuel- The respective lengths of pipe iii are supported in placeby means of brackets iii secured to the body of the-discharge tube bymeans of screws length of pipe .79.. For this purpose, each jacket 18carries a pinion 19, its teeth 82a being meshed with teeth 8la of anarcuate rack 89. A member 8|, extending radially from rack 89, isprovided with a slot 82, serving for reception of one end of lever 83.The opposite end of the lever forms a right-angle elbow 84, being inabutment with a pin 85 actuated by a thermostatic control within saidtube 73.

The right-angle elbow is fulcrumed at 88 so that the expansion of pin 85will swing lever 83 in an are from said fulcrum. As a result, the leverwill cause a limited rotary movement of the rack along an arcuate pathwith respect to the axis of the discharge tube as indicated by dottedlines 8911 shown in Figure 6. Actuating the pinions on jackets E8, therack will cause a swing of the jackets to a position where its jacketwill be interposed between the respective tube 19 and the outer surfaceof the discharge tube l2, making each jacket act as a bafile.

A heavier and more economical fuel, such as kerosene or fuel oil, is tobe supplied to the engine after the initial starting and warming-upperiod of operating said engine on highly volatile fuel from tank 56.This heavier fuel is contained in tank H5 and is conducted by a pipe 89to a rotary pump 99, the latter being operated by a motor 9|. The fuelis forced by the pump to the heating unit 69 through lines 95 and 58. Acheck valve 94 is installed in line 95 and allows fuel to fiow from pump90 to the engine but prevents fuel from flowing back into tank H5 whenthe pump is stopped. The operation of the pump is controlled by athermostatic switch fill, a relay switch I la, and pressure switch 92.

To conclude the description of the parts of my engine, I wish to addthat a valve 96 controls the supply of fuel to nozzles a, said valvebeing operated by means of an electro-magnetic device 91, this beingeither a solenoid or a motor. As a means of igniting the combustiblemixture within the combustion chamber of my engine, I am employing aglow plug 98, best shown in Figures 1 and 2.

In conjunction with the parts already described, I am employing avariety of switches and thermostatic controls to which allusion has beenmade. These are connected by suitable wiring means to a source ofelectric current, such as an electric battery 65, which may be chargedby a generator I I3 operated by a gasoline motor H9.

The supply of current to the respective elements of my engine iscontrolled by means of a series of switches on a control board 99 andconcontrols by means of wire I94 the operation of glow plug 98; while atwo-way switch I05 controls,

by means of wires I96 and 196a, the solenoid 54 controlling supply offuel to the engine from tank 56.

After having described the above parts, I shall describe the operationof my engine as follows:

In starting the engine, switch I93 is first closed,

which allows current to flow to glow plug 98. Next, switch IE5 is closedin order that the solenoid 69 may be energized to open valve 63,permitting fuel to flow from pressure tank 56 up through thefuel-heating unit 69, then through pipe 13 to valve 95. This valve isthen opened by -means of a small, motor device 91, controlled by atwo-way switch Ill-l, permitting fuel to be deo h h ing ube l3 and intomember M, in

openings 21 in shutter 26, next the channels 34 in the flame-arrestingmember 29, and into the combustion chamber H where said mixture isignited by glow plug 98. The ensuing explosion creates a pressure withinthe chamber.

Under the pressure created by the explosion of the fuel mixture, piston45 within cylinder 41 is pushed outwardly, rocking the two-arm lever 52on its fulcrum 43, causing the shutter 25 to be moved upwardly to closeopenings 25 between fins 24 in the difiuser 2 I. As a result thereof,the exploded gases within the chamber have only one way of escaping,namely out through the discharge tube or nozzle I2. Blowing out at highvelocity, they create a partial vacuum in combustion chamber H,whereupon atmospheric pressure outside the combustion chamber will pushthe piston 46 inwardly, returning it to its original position. Themovement of the piston, conveyed to lever 42 by means of connecting rod45, will cause the shutter to be drawn downwardly to bring openings 21within said shutter in register with the openings 25 in the diffuser 21,thus permitting entry of a fresh supply of the air-and-fuel mixture fromthe direction of nozzles 15a, when the cycle will repeat itself andcontinue to do so, each charge being exploded successively by the glowplug in the combustion chamber. The gases resulting from the combustionwill be ejected in successive puffs out of the tail pipe, creating aseries of thrusts in the direction opposite to that of the travel ofsaid gases.

By virtue of the mechanism already described by me, it is possible toaccelerate or to retard the operation of the shutter for admission of anew charge of the air-and-fuel mixture into the combustion chamberfollowing the explosion of the preceding charge. This is effected bymeans of a lever-and-spring combination operated by arm ela of lever 42,By a swing of arm 50 of lever 5|, it is possible to cause spring 58 tobear against said arm 41a downwardly as shown in Figure 1.

In this position, the spring, by means of said arm Ha, will bear againstthe lower part of the shutter 25 in a downward direction and willcounteract the upward thrust of piston 41, thus delaying the closing ofthe shutter. Should said nism, by means of an arm 53.

It may be added here that, after the initial explosion, the glow plugmay be turned off as the wall of the combustion chamber and the elementstherein will be hot enough to ignite the fuel-andair mixture without theneed of any plug.

At this point, I also wish to refer to the flamearresting device. Thereis no novelty in the device by itself, but I am employing it as a partof a combination of elements as shown by me, the device being employedto prevent the flame in the explosion chamber from igniting the fuelmixture before its entry into said chamber..

As already described, I am employing a pump .51, driven by motor 58, forthe purpose of supply- ;liyered towards'nozzles 15a to discharge saidfuel ing air to .tank v56. I am also utilizing in said pump-and-tankarrangem'eiit: a switch 6!! controlling the operation of the motonssaidswitch being responsive to pressure of air within said tank. The tank,it will be noted, is connected to said switch by means of pipe GI. Theswitch is of a type which is, normally, closed and which will open whenthe pressure within the tank reaches 150 lbs. per sq.inch, but willclose when the pressure drops below that limit.

Upona short period of operation of the engine on fuel from tank 55, athermostatic switch I91 will be closed by an element therein responsiveto the rise of the temperature of fuel line 14 when said temperaturehasreached, say, 900 F. The switch, establishing a ground connection forcurrent from battery 55 along lines I08 and H0, will actuate a relayswitch I Ifld, permitting currentto flow along line I i 2 to switch 92and therefrom along line 93 to a motor 9i operating pump $0. Thestarting up of pump 93 will force kerosene or other fuel from tank I I5through lines 95 and 68 to heater '59. It will also bring about anautomatic changeover from starting fuel to running fuel, in thefollowing manner.

A pressure switch 92, operatively connected to fuel line 95, isresponsive to pressure changes therein. The switch is of a type whichis, normally, closed but may be pre-set to open when said pressurereaches 200 lbs. per sq. inch, and to close again when the pressure hasdropped, say, to 195 lbs. per sq. inch. After relay I Illa has closed,then the pressure switch will automatically start and stop motor 9| atthe proper times necessary to maintain the fuel pressure in line 95within the pre-set 195 to 200 pound limits. After pump 90 starts andbuilds up a pressure in line 95 exceeding the pressure in line 62, someof the fuel from line 95 will flow through T 6'1 to check valve 66,closing said check valve and stopping the flow of starting fuel fromtank 56. Pressure switch 89 will cause motor 5-8 tostop and thus preventexcessive pressure from building up in tank 56.

Asalready intimated, the object of the heating device 65 is to bring thetemperature of the fuel up to the most efficient condition, which mustbegas I have'ascertained by experiments, below 1100 degrees I". Toprevent excessive heating of the fuel when said fuel would dissociateand fill the line with carbon, I have employed the means described abovefor shielding said pipe It from the heat radiated by discharge tube I2.The operation of said device is controlled by a thermostaticallyexpanded pin 85 and lever 83.

' Another, simpler species of said control is shown in Figures 8' and 9.This includes a substantially 'arcu'ate rectangular plate I I! disposedbetween fuel-heating lengths of pipe IE3 and the outer surface ofdischarge tube I2. The plate H1, which is provided with a plurality ofslots I I8 withsolid spaces H9 therebetween, is suspended by means ofhinges 20 on cranks I2I mounted on a rotary shaft I22. The latter iscontrolled by the abovesaid. lever 33 by means of a radial arm I23, towhich arm said lever is pivot-ally connected atits outer end. The resultwill be that, when the lever describes an arcuate movement in responseto the expansion of pin 85, whichis shown in Figure l, the shaft I22will be partly rotated,

causing-crank I2! to lift-said plate Ii? so that understood that,normally, the pipes'are exposed to the radiation of heat fromsaid'discharge tube;

"I2 through said :slots H8 and that the shiftof the plate will bringsaid solid spaces I I9 into position between pipes 10 and said dischargetube l2. As a result thereof, the plate I I1 will act as a baffle plateagainst the radiation of heat from tube I2 to pipes I0.

It will be obvious that some details of construction disclosed hereinmay be changed without departing from the inventive principlesdisclosed. What I, therefore, wish to claim is as follows:

1. In a jet engine, including a charging tube at the front for admissionof fuel, a combustion chamber back of the charging tube for combustionof said fuel, and a discharge tube back of said chamber, said dischargetube'to be heated by gases resulting from said combustion, fuel-deliverymeans coniprising tank means with fuel, motor means to create airpressure within said tank means, a fuel-heating unit comprising pipedisposed parallel to the discharge tube for exposure to the radiation ofheat therefrom, pipe means leading from the tank to said heating unitand fuel line to convey fuel from the heating unit to the front end ofthe charging tube, said fuel line terminating in a hollow bracket infront of the charging tube, a plurality of nozzles openfroni said hollowbracket to release fuel in i into the charging tube, baffle meansdisposed between the pipes of the heating unit and the wall of thedischarge tube, and thermostaticcontrol means adjacent the fuel line andresponsive to the rise of temperature thereof to actuate the means, tovary the amount of radiation from the discharge tube towards the pipesof the heating unit.

2. In a jet engine including a charging tube at front for intake of airand fuel, a chamber back of the charging tube, open to the front andrear, fuel-igniting means therein and a discharge tube back of saidchamber, said tube being heated by gases of combustion, a tank withliquid fuel, compressor means to keep the fuel under pressure, afuel-heating unit disposed adjacent to and exposed to the radiation ofheat from said discharge tube, pipe means to convey fuel from the tankto the fuel-heating unit, baffie means between said heating. unit andthedischarge tube; a fuel lineto convey fuel froin the heating unit to thefront of the charging tube, s rayer means at the outer end of said fuelline to release" fuel in jets into the charging tube, thermostaticcontrol means adjoining said fuel line and responsive to the temperaturechanges thereof to actuate saidbaiiie means to control the amount ofradiation from the discharge tube towards the pipes of the heatingunit.

In a jet engine including, in axial alignment, charging tube having afront end for intake of fuel, a chamber for COillbllStlOll of the fuelback of the chargingtube and a discharge tube back of said cham iber,said tube being heated by gases of combustion, a tank with liquid fuel,compressor means to keep the fuel under pressure, a fuel-heating unitcomposed of a pipe in a plurality of parallel lengths, the heating unitbeing disposed-adjacent to'and'exposed to the radiation of heat from thedischarge tube, baffle means between said heating unitand the dischargetube,

a pipe to convey the'fuel from the tank into the heating unitand a pipeleading therefrom to the front end of the: charging tuba. sprayer meansat the outer end of the last-named pipe to release fuel in jets into thecharging tube,.thermostatic control means" adjoining said last-namedpipe and responsive to the temperature changes thereof, to actuate saidbafiie means to control the amount of radiation from the discharge tubetowards the pipes of the heating unit.

4. In a jet engine including, in axial alignment, a charging tube at thefront for intake of a fueland-air mixture, said charging tube includinga cylindrical member and a frusto-conical member expanding rearwardly ofsaid cylindrical member, a chamber for combustion of the fuel-and-airmixture back of the charging tube, and a discharge tube back of saidcombustion chamber, said tube being adapted to be heated by the gases ofcombustion, a tank with a liquid fuel, compressor means to keep the fuelunder pressure, pipe means to convey fuel from the tank to the front ofthe charging tube and including a fuelheating unit, said unit comprisinga plurality of lengths of fuel-conveying pipe, a rotary jacket,semi-circular in cross-section, adjoining each length of the pipe andextending parallel thereto, thermostatic control means responsive to therise of temperature of the fuel-conducting pipes, to swing the jacketsinto position between the pipe lengths of the heating unit and saiddischarge tube, sprayer means at the outer end of the fuel- 1%?)conveying means, to release fuel in jets into the charging tube,thermostatic control means responsive to the temperature changes of themeans to convey fuel from the heating unit to the sprayers, to actuatesaid jackets to shield the pipes of the heating unit against heatradiated from said discharge tube.

JOHN J. WALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,405,482 Bostedo Feb. '7, 19222,124,462 Cummings July 19, 1938 2,142,601 Bleecker Jan. 3, 19392,395,113 Goddard Feb. 19, 1946 2,435,990 Weiler Feb. 17, 1948 2,446,266Cummings Aug. 3, 1948 2,479,776 Price Aug. 23, 1949 2,483,045 HarbySept. 2 1949 2,496,351 Mazzoni Feb. 7, 1950 2,505,757 Dunbar et a1 May2, 1950

